As an important switching control element, a thin-film transistor plays a key role in the display device. In the prior art, for making a display device have better image display quality, a thin-film transistor (TFT) structure is usually disposed in a display panel of the display device. The TFT structure includes two types of TFTs, in which one TFT has the advantages of high mobility and rapid charging, and the other TFT has the advantage of low leakage current. For instance, the TFT structure will usually be arranged in an organic light-emitting diode (OLED) display panel. The TFT structure includes a first TFT and a second TFT. The first TFT is a low-temperature polysilicon thin-film transistor (LTPS-TFT), and the second TFT is a metal oxide TFT. When the display device provided with the OLED display panel displays an image, OLED elements in the OLED display panel are driven by utilization of the advantages of high mobility and rapid charging of the first TFT and the low leakage current of the second TFT, so that the display device can have good image display quality.
However, when both the first TFT having the advantages of high mobility and rapid charging and the second TFT having low leakage current are simultaneously arranged in the display panel, an active layer of the first TFT is usually doped with hydrogen (e.g., the low-temperature polysilicon thin-film transistor); the second TFT is usually a metal oxide TFT, namely a material of an active layer of the second TFT is metal oxide; and the metal oxide as the active layer of the second TFT is very sensitive to hydrogen. Therefore, when the both the first TFT having the advantages of high mobility and rapid charging and the second TFT having low leakage current are simultaneously arranged in the display panel, the hydrogen in the active layer of the first TFT may be diffused into the active layer of the second TFT and causes adverse effects on the active layer of the second TFT, and then adversely affects the performances of the second TFT.